The market offers various systems for producing cooked ham (and like products) and in particular in loaf shapes, whole or transversally fractioned, a production of which provides considerable advantages for the sold and sliced product as it notably increases the performance of the slicing and packing lines, as well as reducing waste at the ends of the loaves.
According to the most tried and tested technology, semi-worked products destined for production of loaves are cooked in waterproof casings where the product is not in contact with the air (termed “vacuum cooking”) in order to improve the compactness and single-body-effect of the product.
This technology includes the introduction of ham or shoulder (but can be applied to white meats and in any case for meats in general) in waterproof packs which are housed in moulds which impress on them a particular shape which during cooking thereof will become stable.
The waterproof packs are advantageously, though not exclusively, constituted by bags made of a flexible and heat-weldable plastic material, which are filled with the product (meat, possibly treated by injection of saline solutions and massaged by suitable machines), and are then vacuum-sealed such as to hermetically insulate the meat placed in the bag from the outside environment.
The introduction of the meat into the bags can be done in various ways. A first of these modalities comprises housing the empty bags directly in the moulds, introducing the meat and finally heat-welding the bags under vacuum by special machines (vacuum heat-welders).
A second of the modalities includes housing the empty bags, or pre-formed bags, internally of containers (“false moulds”), introducing the meat, heat-welding the bags (or pre-formed bags) under vacuum using special machines (heat-formers and/or capsule fillers, according to the specific case) and finally transferring the thus-prepared products internally of the moulds.
A third modality involves the use of vacuum-bagging machines for inserting the meat in “tubes” of flexible plastic material, which are then closed at ends thereof by stapling machines, forming closed bags which are then transferred internally of the moulds.
Whatever method chosen for introducing the meat into the bags, the present invention relates to the moulds in which the bags are housed for forming and cooking the meat. In general, the moulds can be made in two ways.
The first of these relates to single moulds comprising:
a bottom die made in the form of a recipient for containing the meat, with a concavity of the recipient facing upwards;
a cover for closing the bottom die and sliding internally of the upper mouth of the concavity;
a contrast element constrained to the bottom die, and elastic pushing means for pushing the cover to compress the meat contained in the bottom die, interposed between the cover and the contrast element (producers of these moulds are: Menozzi, Manzini, Riva and other international producers).
The products are obtained by positioning the bag internally of the bottom die and positioning the product, then closing the bag about the product, possibly by vacuum heat-welding), positioning and pressing the cover, and thus subjecting the product to cooking while contained in the mould.
The muscle bundles resulting from the anatomical sectioning of the animal can be placed in the moulds, which leads to a spatial conditioning of the product in the bottom die, which in this case produces a slice of meat which is similar to a product cooked whole, with better results in terms of performance and firmness of the slice.
The products are differentiated in products either without or with “weight loss”, i.e. with a reduction in weight, which occurs because during cooking of the meat a liquid or gelatinous part (the “exudate”) separates out, which in the case of vacuum cooking remains inside the cooking bag.
Owing to this phenomenon, an extra part has to be included in the sealed bag, which part is empty at the start and in which the exudate collects during the cooking stage, such that the exudate does not remain internally of the final product.
“Weight loss” relates to products exhibiting, in the cooking bag, a presence of exudate exceeding 3%.
As a general rule, though not to be taken too literally, the greater the weight loss the greater the quality of the final product.
The above-described moulds optimally exploit the weight-loss method and can also accept relatively-high weight loss, as they enable the exceeding part of the bag to be arranged flanked and parallel to the product, outside the mould.
While permitting top-quality production, these moulds do not permit efficient and rational use of traditional ovens, in which it is industrially necessary to insert the product in regular and rational stacks, this being a consequence of the moulds' being shaped such that they are not stackable in a satisfactory way.
It is not possible to stack the moulds vertically one on top of another because the weight bearing on the lower moulds varies the pressure with which the meat is compressed by the mould cover, with resulting variations in the product quality, in some cases producing excessive and unacceptable pressures. Additionally the stacked moulds are not sufficiently stable.
A known method for stacking these moulds involves arranging them in a vertical pyramid formation, when each bottom die bears directly on two underlying bottom dies.
This stacking method poses various technical problems, the first being stability. Furthermore, the interspace between the bottom dies is relatively small and does not permit an efficient circulation of cooking steam between the moulds, with resulting poor temperature distribution; nor does this method enable arrangement of the exceeding parts of the bags outside the cavities of the bottom die along the longitudinal flanks of the mould, preventing good weight-loss performance.
In practice, the technology that involves the use of the moulds described above applies different means for handling moulds inside ovens, including transport systems with suspended tray conveyors which, however, require investment in expensive plants in which there is anyway a poor exploitation of the internal volume of the ovens.
In all cases, the risk of puncturing the bags is high, especially in the part thereof which is outside the mould, and the desired technological results are impossible to reach. Furthermore, “traditional” type moulds are not frequently used for the production of loaves, due amongst other things to handling problems caused by the weight, constructional shape and especially the difficulties of subjection to automated movement.
A second realisation includes, as a rationalisation of the stacking of products undergoing treatment in the cooking ovens, and for obtaining both the above-mentioned loaves of greater length and already-fractioned ones, the use of large trays superposable in columns and each comprising a plurality of mould bottom dies in upper position and an equal plurality of covers, fixed or slidable, located in the lower part of the tray, which close and press the products placed in the bottom dies of the underlying tray (producers of these include Armohnox, Kaufler, Creminox, Roser and others).
In this case, the meat cannot be bagged directly in the trays, so first it is necessary to fill the bags and place them under vacuum conditions using “dummy moulds”, either using heat-formers or vacuum baggers and staplers connected thereto, after which the bags filled with meat are collected and transferred internally of the bottom dies of the trays.
This transfer stage leads not only to an inevitable displacement of the meat in the bags, especially in the case of higher quality foods, but is also an excessively laborious task for the operatives, as these are tasks that cannot be performed automatically. In some realisations the lower part of the trays includes covers which can slide with respect to the bottom die of the underlying tray.
The sliding is normally used to obtain products with weight loss, but in this case the weight loss is technologically limited by the possibility of collecting exudate which, for constructional reasons, can happen only in the heads of the bottom dies.
The slidable covers are further constrained to one another such as to be able to perform only one same displacement, such that a single cover cannot slide in the relative bottom die independently of the others.
The cooking of the products contained in the stacked trays can be done in suitably-modified steam ovens, or can be done by recycling of water in special hollow spaces (a system which is practically limited to products without weight loss), or even by immersion in water-filled baths.